Check valves are valves that allow fluid flow in one direction therethrough and prevent flow in the opposite direction. They are widely used in a range of applications, for example in air conditioning systems, for example in aircraft air conditioning systems.
Check valves commonly include at least one, typically a pair of, valve flappers located at an opening in a valve housing. The flappers are hingedly supported on a hinge pin mounted to the valve housing for rotation between a closed position in which they lie across and close the opening, preventing fluid flow through the opening in one direction and an open position in which, under the pressure of a fluid (gas or liquid) on one side of the check valve, the flappers rotate from their closed positions so as to allow the fluid to flow through the valve in the opposite direction. The flappers typically have hinge lugs which engage over the hinge pin. Discontinuities in the flapper between the hinge lugs may in some cases lead to stress concentrations in the flappers.
A stop is provided to limit the rotational movement of the flapper elements as they open. The stop may comprise a stop pin which is mounted to posts arranged on opposed sides of the valve housing opening. In other embodiments, a more substantial stop may be provided, extending across the valve opening, providing a larger contact area with the flappers. An example of such a stop is disclosed in US 2013/340862 A1. This may help the stop better absorb the impact of the flappers as they engage the stop. However, such stops may be difficult to manufacture, often requiring complex machining from a large block of material.
The present disclosure provides a check valve with a different hinge and stop arrangement.